In more and more collaborative or so called crowdsourcing applications users of computer systems contribute data content to those applications. In such scenarios often a trade-off between privacy of the user and accountability of contributed data has to be found. However, privacy of user data and accountability of content are key elements in providing trustworthy services. Generally, systems either favor privacy of the user or guarantee accountability. Privacy of data has two different aspects: the right of the user to disclose or not disclose his or her identity and the user's control over the contributed data provided. However, control over the contributed data requires accountability to some extent. Accountability on the other hand means that the origin or any manipulation of the data is traceable so that a respective user is accountable for the data. This is in contraction to the privacy aspect of non-disclosing the user's identity.
On the one hand, users should be provided with a maximum of privacy, e.g., non-disclosure of their current location or taken routes, in order to favor unconcerned participation. On the other hand, participation should be reimbursed (incentives, access to content provided by others, etc.), so users are motivated in order to join in the crowdsourcing application and hence accountability is required to some extent. In current implementations the tradeoff between privacy and accountability has to be found.